diff options
Diffstat (limited to 'src/Utility')
| -rw-r--r-- | src/Utility/ConcurrentOutput.hs | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/Utility/ConcurrentOutput.hs b/src/Utility/ConcurrentOutput.hs index 1ca92d90..c6550b84 100644 --- a/src/Utility/ConcurrentOutput.hs +++ b/src/Utility/ConcurrentOutput.hs @@ -1,6 +1,7 @@ -- | Concurrent output handling. module Utility.ConcurrentOutput ( + withConcurrentOutput, outputConcurrent, createProcessConcurrent, ) where @@ -113,6 +114,18 @@ updateOutputLocker l = do putMVar lcker l modifyMVar_ lcker (const $ return l) +-- | Use this around any IO actions that use `outputConcurrent` +-- or `createProcessConcurrent` +-- +-- This is necessary to ensure that buffered concurrent output actually +-- gets displayed before the program exits. +withConcurrentOutput :: IO a -> IO a +withConcurrentOutput a = a `finally` drain + where + -- Just taking the output lock is enough to ensure that anything + -- that was buffering output has had a chance to flush its buffer. + drain = lockOutput (return ()) + -- | Displays a string to stdout, and flush output so it's displayed. -- -- Uses locking to ensure that the whole string is output atomically |